Device and method for finding the center and reading the setting of an implantable medical device

ABSTRACT

A centering tool and a combined centering-indicator tool for finding the magnetic center and indicating the setting of an implantable adjustable valve. The centering and combined centering-indicator tools include a magnetic capsule movable within a cavity to a target located on the tool when the magnetic capsule is centered over magnet of an adjustable valve.

BACKGROUND

The present disclosure relates to implantable medical devices such asfluid flow control devices including adjustable valves and also relatesto tools for determining the location and settings of an adjustablevalve. More particularly, the present disclosure relates to tools forfinding the magnetic center and indicating a setting of an implantableadjustable valve.

Generally, a fluid flow control device includes a one-way control valvefor controlling the flow of cerebrospinal (CSF) fluid out of a brainventricle and preventing backflow of fluid into the brain ventricle.Hydrocephalus, a neurological condition which may affect infants,children and adults, results from an undesirable accumulation of fluids,such as CSF, within the ventricles, or cavities, of the brain and whichaccumulation may exert extreme pressure with brain and skull deformingforces, the latter in infants. Treatment of hydrocephalus often involvesdraining CSF away from the brain ventricles utilizing a drainage orshunt system including one or more catheters and a valve which maygenerally be described as a fluid flow control device or shunt valve.The shunt valve, or fluid flow control device, may have a variety ofconfigurations and may be adjustable in that the valve mechanism of thedevice may be set to a threshold pressure level at which fluid may beallowed to begin to flow through the valve and drain away from thebrain. Shunt valves may be subcutaneously implantable and percutaneouslyadjustable to various pressure settings. Examples of fluid flow controldevices are disclosed, for example, in U.S. Pat. No. 5,637,083 entitled,“Implantable Adjustable Fluid Flow Control Valve”, and U.S. patentapplication Ser. No. 13/804,875 entitled, “Fluid Flow Control Devices,Rotors and Magnets with Increased Resistance to Inadvertent SettingChange and Improved Accessory Tool Coupling”, incorporated by referenceherein in their respective entireties.

Adjustable valves may include magnetic components which allow anexternal tool or tools to selectively and non-invasively determine thesetting of the implanted valve and adjust the setting to a desiredpressure. A tool set typically includes: a locator tool, which allowstactile determination of the orientation and position of the implantedvalve; an indicator tool, to determine the current setting of theadjustable valve and confirm new settings of the valve after the newsettings have been implemented; and an adjustment tool to change thesetting of the valve. The tools are designed to externally (i.e.,external to a patient) couple with a magnet of the adjustable valve suchthat upon coupling, the setting of the valve may be determined and thevalve magnet may be deliberately manipulated to thereby adjust thepressure setting of the valve without removal of the subcutaneouslyimplanted device. Indicator and adjustment tools thus rely on magneticcoupling of the tool to the adjustable valve, where the magneticcoupling is strong enough to determine or to adjust the position of thevalve magnet even through tissue (e.g., a patient's scalp). Examples oflocator, indicator and adjustment tools are shown, for example, in U.S.Patent Application Publication No. 2002/0022793 (hereinafter, “the '793application”) to Bertrand et al. entitled, “Tool for Adjusting anImplantable Adjustable Fluid Flow Control Valve” and U.S. Pat. No.6,883,241 to Moskowitz, et al., entitled, “Compass-Based Indicator withMagnetic Shielding”, incorporated by reference herein in theirrespective entireties.

Locator, indicator and adjustment tools may be used in conjunction withone another. For example, after the tactile determination of a valve'sposition has been made in conjunction with a locator tool, an indicatorand/or adjustment tool may be positioned in a location determined by thelocator tool. In other words, an indicator and/or adjustment toolposition may be based off of or may be “keyed to” the locator toolposition. The position of an adjustable valve, as determined by thelocator tool, allows the indicator and/or adjustment tools to be placedin sufficient proximity to the magnetic components of the implantedvalve such that the valve magnet or magnets align and/or couple with themagnetized tool elements or magnets. However, the magnetized element ofan indicator tool may tend toward alignment with the earth's magneticfield if the pull of the magnet in the implanted valve is notsufficiently strong (such as when the distance between the implantedvalve magnet or magnets and the tool increases) and could lead toinaccurate device setting determinations or indications.

In addition, magnetic components of the adjustable valve itself may besusceptible to movement or inadvertent setting adjustment by strongnearby magnetic fields since the internal magnetic elements of a valvemay tend to align with an external field. An adjustable valve mighttherefore be unintentionally adjusted when in the presence of a strongexternal magnetic field, such as encountered in a magnetic resonanceimaging (MRI) procedure. Thus, some fluid flow control devices includefeatures which provide increased resistance to inadvertent settingchanges. For example, mechanical “stops” or magnet configurationsdesigned to resist strong nearby magnetic fields may be incorporatedinto a device such as disclosed, for example, in U.S. patent applicationSer. No. 13/804,875, referred to above. Deliberate adjustment of thesetypes of valves, in some cases, may be more difficult to achieve withoutan accurate alignment of the adjustment tool to the valve magnet.

In order to accurately magnetically align or couple a tool to animplanted valve (for example, to avoid effects of the earth's magneticfield on the tool or to ensure a sufficient coupling of a tool to avalve for valve setting indication and adjustment purposes), it may thusbe desirable to find the magnetic center of the valve magnet and therebyposition a tool in magnetic alignment with the magnetic center of thevalve magnet. Aligning an external tool with the magnetic center of thevalve can provide coupling of the tool to the valve which allows anaccurate or more accurate reading of a valve setting and allowsdeliberate adjustment of the valve to be carried out, even where thedistance between the implanted valve and the external tool is increased,and/or in cases where an implantable valve is designed for increasedresistance to inadvertent setting changes.

The '793 publication depicts examples of tools which may be useful withan adjustable valve and which may be used in conjunction with thecentering and centering-indicator tools 50, 150, 250 (FIGS. 3, 6, 7) ofthe present disclosure. The '793 publication describes a locator toolcomprising a tube with a central opening and a slot. An index on thetube is for visually indicating the settings of a valve, e.g., 20, whenthe locator tool is aligned with the valve. The locator tool alsoincludes a protrusion extending inwardly into the central body as wellas a fluid flow direction indicator. An indicator tool may comprise anindicator central body a compass having a magnetized pointer, an indexfor indicating possible positions of the adjustable valve correspondingto the different valve settings, and a ridge for interacting with theprotrusion of the locator tool.

As further described in the '793 publication, the locator centralopening allows locator tool to be oriented to and aligned with animplanted valve in a predictable manner and allows the physician topalpate the implanted valve through opening. In use, after orientationof the implanted valve has been established by locator tool, indicatorcentral body is placed within tube of locator tool. Indicator andlocator tools may comprise alignment features. For example, whenindicator central body is placed within tube, a ridge of the indicatortool aligns and interacts with a slot of the locator tool to preciselyorient the indicator tool with the locator tool. Other alignmentfeatures of the indicator and locator tools are contemplated. In anyevent, placement of indicator tool into locator tool allows theindicator tool pointer to interact with and align itself with the magnet120 of the valve 20. This will cause the pointer to point to a spot onthe index indicating the position of the magnet 120 of the valve 20. Theposition of the magnet 120, as described above, indicates the setting ofthe valve.

The '793 publication further describes an adjustment tool having amagnet fixed in place in an adjustment central body, an indentation andan arrow. Adjustment central body may include a series of indentationsconfigured to interact with a protrusion on the locator tool.Indentations may be spaced around the periphery of the adjustmentcentral body corresponding to the location of the settings of the valve20. In use, the adjustment tool is positioned above the locator toolwith the arrow aligned with the pressure level setting on index, thepressure level setting of the valve having been determined previously bythe indicator tool as described above or by other methods such as x-rayor fluoroscopy. Maintaining alignment, the adjustment tool is loweredtoward the locator tool until the adjustment central body enters thetube. Where an indicator tool has been used to determine the valvesetting, the indicator tool is removed prior locating the adjustmenttool into the locator tool. The protrusion on the locator tool interactswith an indentation on the adjustment central body corresponding to thecurrent valve setting. In this position, the adjustment tool magnetcouples with the valve magnet and the adjustment tool is rotated so thatthe arrow points to the desired valve setting indicated on index.

Other examples of devices for locating, indicating and adjusting thesetting of an adjustable valve are described in U.S. Pat. No. 7,334,582to Bertrand, et. al., “Electronic Valve Reader”, U.S. Pat. No. 8,015,977to Bertrand, et. al., “Indicator Tool for Use with an ImplantableMedical Device”, and U.S. Pat. No. 8,257,296 to Bertrand et. al.,“System Including an Implantable Medical Device and Electronic ValveIndicator and Locator Device”, incorporated by reference herein in theirrespective entireties.

U.S. Pat. No. 7,921,571 to Moureaux et al., “Device for MechanicallyLocating and Reading the Setting of An Adjustable Valve” proposes adevice for mechanically and reading the setting of an adjustablemagnetic valve which describes a three-dimensionally pivoting compassincluding a needle and pin mounted on a pivot.

SUMMARY

Devices according to the disclosure include a centering tool having ahousing including a cavity and a magnetic capsule disposed in the cavitywhere the magnetic capsule comprises a tool magnet. The magnetic capsuleis configured to move within the cavity to center within a target on thetool when the tool magnet is magnetically aligned with a magnet of anadjustable valve.

In some embodiments, a combined centering-indicator tool includes ahousing including a cavity and an index on the housing comprisingadjustable valve setting values, a magnetic capsule disposed within thecavity comprising a tool magnet and a pointer, and a target. Themagnetic capsule is configured to move within the cavity to centeritself within the target when the tool magnet is magnetically alignedwith the magnetic center of the adjustable valve magnet and can rotatewith respect to an axis of the capsule such that the pointer rotates topoint to a valve setting value on the index.

In some embodiments, a system includes a locator tool having a tube forreceiving a centering tool or a combined centering-indicator tool, thecentering tool or combined-centering tool including a housing and acavity, a magnetic capsule disposed within the cavity and a targetprovided on the centering or centering-indicator tool, where themagnetic capsule is configured to move within the cavity to centeritself within the target when the tool magnet is magnetically alignedwith the magnetic center of an adjustable valve magnet, the magneticcapsule also configured to rotate within the cavity. Where the toolincludes an index and a pointer on or part of the magnetic capsule,rotation of the magnetic capsule may allow the pointer to rotate topoint to a valve setting value on the index when the tool magnet isaligned with the valve magnet. The centering or combinedcentering-indicator tool is configured to be positioned within the tubeof the locator tool when the locator tool is in proximity to theimplanted adjustable valve.

In some embodiments including those described above, the magneticcapsule can be visible through a wall of the housing and may comprise amagnetic capsule housing having various shapes including a circular ordisk-like shape. The tool magnet may include one or more magnets andeach magnet may include vertical or horizontal polarity. Tool magnets ofthe present disclosure can also include a metal strip or strips or aHalbach array for strengthening the magnetic field to a side of the toolmagnet. The target may have a perimeter substantially the same size asor slightly larger than the perimeter of the magnetic capsule or themagnetic capsule housing. A fluid may be disposed within the cavity andthe magnetic capsule may move within the fluid.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an adjustable flow control valve.

FIG. 2 is a side cross-sectional view of the valve of FIG. 1.

FIG. 3 is a perspective view of a centering tool.

FIG. 3A is a side cross-sectional view of the centering tool of FIG. 3.

FIG. 3B is a perspective view of the centering tool of FIG. 3 with amagnet capsule in a position within the centering tool.

FIG. 4 is a top view of a magnet capsule according to an embodiment.

FIG. 4A is a side cross-sectional view of the magnet capsule of FIG. 4.

FIGS. 5A-5F are illustrations of magnet configurations.

FIG. 6 is a perspective view of a combined centering-indicator tool.

FIG. 6A is a side cross-sectional view of the combinedcentering-indicator tool of FIG. 6.

FIG. 7 is perspective view of a combined centering-indicator tool.

FIG. 7A is a side cross-sectional view of the combinedcentering-indicator tool of FIG. 7.

FIG. 8 is a side view illustration of a tool and an adjustable valve.

FIG. 9A is a cross-sectional side view illustration showing a step in amethod of using a tool according to an embodiment.

FIG. 9B is a cross-sectional side view illustration showing a step in amethod of using a tool according to an embodiment.

FIG. 9C is a cross-sectional side view illustration showing a step in amethod of using a tool according to an embodiment.

DETAILED DESCRIPTION

The present disclosure provides centering and combinedcentering-indicator tools (e.g., 50, 150, 250 FIGS. 3, 6, 7) which maybe used cooperatively or in conjunction with other tools such as alocator tool, an indicator tool or an adjustment tool. Centering andcombined centering-indicator tools disclosed herein may also be usedindividually or in paired relationships with locator, indicator oradjustment tools as further explained hereinafter. In addition, thetools described herein may be useful with a variety of medical devicesincluding, but not limited to, a variety of implantable magneticallyadjustable valves which may or may not include features designed toprovide resistance to inadvertent setting changes.

FIG. 1 depicts one example of a fluid flow control device 20, which maybe useful with or used in conjunction with the centering andcentering-indicator tools (50, 150, 250, FIGS. 3, 6, 7) of the presentdisclosure. Fluid flow control device 20 includes an inlet connector 22,configured to fluidly connect to a catheter (not shown) which may beinserted through a patient's skull into a brain ventricle containing CSFunder pressure, and an outlet connector 24, configured to fluidlyconnect to a distal catheter which serves to direct CSF to anotherlocation in the patient's body. FIG. 2 depicts a cross-sectional view ofthe fluid flow control device of FIG. 1 taken along section 2-2, and anexternal tool 140 positioned above the device 20. Fluid flow controldevice 20 includes a fluid reservoir 60, a valve mechanism 38, and arotor assembly 100. Rotor assembly 100 includes a valve magnet 120 ormagnets and is configured to rotate in response to an applied magneticfield such as when encountering a magnetic tool 140.

As also described in U.S. patent application Ser. No. 13/804,875, therotor magnet 120 may include a single magnet or dual magnets withhorizontally or vertically aligned polarity. Rotor assembly 100 may beprovided within a cartridge assembly 40 and may include an element suchas a groove or a notch (not shown) which interacts with an element on aportion of the cartridge assembly 40 such as a spline or a tab (notshown). By including a particular magnet orientation or interactingelements on the rotor assembly 100 and cartridge assembly 40, the rotorassembly 100 may have an increased resistance to undesired rotation andtherefore the valve 20 may have an increased resistance to inadvertentpressure setting changes, such as when a patient having an implantedvalve is in the presence of a strong magnetic field (e.g., an MRIdevice).

As described above, it may be desirable to locate the center of thevalve magnet 120 prior to making a valve setting determination and/orprior to adjusting the valve setting. As also described above, findingthe magnetic center of valve 20 may serve to more easily, accurately orprecisely align and couple an external tool 140 to the valve. Theremaining Figures depict embodiments of centering andcentering-indicator tools and tool elements useful with devices (e.g.,adjustable valves) and/or useful with various locator, indicator oradjustment tools.

FIGS. 3 and 3A depict a centering tool 50. Centering tool 50 includes ahousing or container 60, which is depicted in FIGS. 3, 3A as havingcircular disk shape. However, housing 60 may comprise various othershapes and configurations including circular, spherical, polygonal orother shapes. Nevertheless, housing 60 includes a housing bottom wall62, side walls 64, upper wall 66 and a cavity 70. Cavity 70 is definedby a cavity floor 72, cavity side walls 74 and a cavity top or ceiling76. Cavity 70 may be filled with a substance such as an oil or otherliquid (not shown), for example, a mineral oil or other fluid, forexample any fluid which may be useful as a compass oil. A dense fluidmay be used so as to provide buoyancy to the magnetic capsule 80 orallow for the magnetic capsule 80 to be neutrally buoyant. For example,a perfluorochlorcarbon may be used. Other fluids are also contemplated.

Provided within cavity 70 is a magnetic capsule 80 and a target 81. Ingeneral terms, magnetic capsule 80 (also 80′, 80″, FIGS. 3, 4, 6, 7hereinafter generally referred to as magnetic capsule 80), is configuredto move (e.g., slide) within cavity 70 and center itself within thetarget 81 when the target 81 of the centering tool 50 is centered over avalve magnet (e.g., valve magnet 120 of valve 20). Magnetic capsule 80is configured to freely move within cavity 70 (e.g, in a lateral orrotational manner as explained below) such that magnetic capsule 80 isnot connected or attached to any portion of cavity 70. Magnetic capsule80 may thus slide freely within cavity 70. Use and operation of thecentering tool 50 will be further described below. Magnetic capsule 80may be constructed in a variety of configurations and may, for example,include a capsule housing 82 for encapsulating or housing one or moretool magnets 84. Alternatively, capsule 80 may be constructed with nohousing 82 (i.e., tool magnet 84 does not include a housing 82). Instill further alternative embodiments, housing 82 may be provided on oraround only a portion of magnet 84, for example, only a bottom portion,a top portion, a side portion, or a combination thereof, of magnet 84.Magnetic capsule 80 may comprise a variety of spherical, cylindrical,polygonal, or other shapes including an arrow-shape, such as depicted inFIG. 4. The configuration or shape of capsule 80 may be defined by theshape of the tool magnet 84 or magnets (i.e., may be defined by themagnet configuration), or may defined by the shape of housing 82 inwhich the tool magnet or magnets 84 may be encapsulated, enclosed orotherwise provided within. Thus, for example, the form of the magnetconfigurations 91, 93, 95, 97 (FIGS. 5A-5E) themselves may define theshape of capsule 80. Or, capsule 80 may be in the form of housing 82,such as magnetic capsules 80, 80′, and 80″ (FIGS. 3, 4, 6, and 7).

Tool magnet 84 may likewise comprise several different magnetconfigurations. Some non-limiting examples of the magnet configurationscontemplated by the present disclosure are depicted in FIGS. 5A-5F. FIG.5A depicts one embodiment of a magnet including a single magnet 91having a squared shape and including a horizontal magnet polarity P_(H)where the direction of polarity is perpendicular to a vertical magnetaxis A. Alternatively, single magnet 91 could comprise other shapes suchas a circular (for example magnet 84 as depicted in FIG. 4), spherical,polygonal or other shape. FIG. 5B is a top view of another embodiment ofa magnet. Magnet 93 comprises two magnets M1, M2, adjacent one another.FIG. 5C is side view of magnet 93. Magnets M1 and M2 of FIGS. 5B and 5Care depicted as circular disks but may alternatively comprise severalother shapes such as described with reference to FIG. 5A (e.g.,spherical, square etc.). Magnet 93 may comprise horizontal polarity, asdescribed above with respect to magnet 91 of FIG. 5A, or magnets M1 andM2 may comprise vertical polarity P_(V) (FIG. 5C) such that polarity ofeach magnet is parallel to a vertical magnet axis A. For example, asdescribed in the U.S. patent application Ser. No. 13/804,875, includingvertically polarized magnets in a device can provide a device having areduced tendency to undesirably align with a magnetic field. Thus, ifmagnet 84 (FIGS. 3, 6, 7) includes vertical polarity, magnet 84 (andtherefore magnetic capsule 80) may have less tendency to align with anexternal magnetic field, (such as that created by an MRI device or suchas the Earth's magnetic field).

FIG. 5D is a top view of another embodiment of a magnet depicting magnet95 comprising three magnets M1, M2, M3 having a horizontally alignedpolarity P_(H). Magnets M1, M2 and M3 are depicted as spherical orball-shaped magnets, however, as described with reference to FIGS. 5Aand 5B, magnets M1-M3 may likewise include other shapes or geometries.

FIG. 5E shows a side view of another embodiment of a magnet depicting amagnet 99 comprising two magnets, M1 and M2 having vertical polarityP_(V) and a strip or element 98 disposed on the top “T” of the magnet99. As with magnets 91, 93, and 95, magnets M1 and M2 of magnet 97 mayalternatively include horizontal polarity and may include any of thevarious shapes described above. Strip 98 has a thickness “t_(p)” and maycomprise metal and for example may comprise steel. Strip 98 may beattached to magnets M1, M2 via magnetic attraction between the two.Strip 98 may be constructed of a ferromagnetic material such as iron orsteel and the thickness “t_(p)” of strip 98 may be less than a thickness“t_(m)” of magnet 99 and may in some embodiments comprise a thin metalmagnet. Providing strip 98 at the top of magnet 97 may effectivelyweaken the magnetic field at the top “T” of magnet 97 whilestrengthening the magnetic field toward the bottom “B” of magnet 97.This strengthening of the magnetic field at the bottom of magnet 97 mayallow for better coupling of tool 140 to valve magnet 120 of animplanted valve 20. Another magnet configuration is shown in FIG. 5F.Magnet 99 comprises a Halbach array which includes magnets H1, H2, H3having magnetization illustrated for each magnet by arrows A1, A2, A3.The Halbach array may include additional magnets, such as shown in FIG.5F in phantom, with magnetization of each magnet rotated with respect toan adjacent magnet in a pattern as known for Halbach arrays. It is to beunderstood that any number of magnets may be utilized with the Halbacharray. As is known, a Halbach array augments a magnetic field on oneside of the array while cancelling the field to near zero on the otherside via the spatially rotating pattern of magnetization of the magnetsof the array. Thus, providing a magnet 99 configured as a Halbach arraymay strengthen the magnetic field below the array and serve to create astronger coupling of magnet 99, and thereby magnetic capsule 80, to avalve magnet 120.

Returning to FIG. 3, housing 82 may comprise a variety of suitablematerials including metals or polymers or combinations thereof andspecifically non-magnetic materials. In some embodiments, the housingmaterial is clear, transparent or see-through whereby magnetic capsule80 is visible through housing 82 (and in some embodiments, inparticular, through housing upper wall 66), such as depicted in FIGS. 3,4, 6 and 7. In addition, a portion or portions of housing 82 may beconstructed of one material while another portion or portions of housing82 may be constructed of another or different material. Regardless, thematerial of housing 82 may be designed to allow for ease of movement ofmagnetic capsule 80 within cavity 70. Thus, housing 82 may beconstructed of a material designed to reduce friction between magneticcapsule 80 and cavity walls 72, 74 and 76. For example, housing 82 maybe constructed of PTFE, acetal or other materials.

Magnetic capsule 80 may be configured to slidably move, float or suspendwithin cavity 70 and may be configured to rest on or float just abovecavity floor 72 or may be configured to be suspended within cavity 72 atany distance between cavity floor 72 and cavity top or ceiling 76. Insome embodiments the space between the magnetic capsule and the floor 72is limited and configured to be as small as possible so as to keep themagnetic capsule 80 as close to the floor 72 as possible therebyproviding a closer relationship between the magnetic capsule 80 and thevalve magnet 120. Regardless, magnetic capsule 80 is configured tocenter within a target 81 when positioned over the magnetic center of amagnet (e.g., 120, FIG. 1) of an adjustable valve (e.g, 20, FIG. 1).Target 81 comprises a marking at a location on the tool 50 such as onthe floor 72 or ceiling 76 of cavity 70, other positions for target 81are also contemplated. The target 81 is located on device 50 such thatwhen the approximate center of the device 50 is centered over a valvemagnet 120, the tool magnet 84 or magnetic capsule 80 will movelaterally with respect to cavity floor 72, to the center or approximatecenter of the target 81. Thus, in an embodiment, capsule 80 may slidealong or just above the floor 72 of cavity 70 until capsule 80 iscentered over the valve magnet 120 of an implanted valve at which pointthe magnetic attraction between the tool magnet 84 and valve magnet 120causes the magnetic capsule to center within the target 81. For example,a user may move the device 50 until magnetic capsule 80 is substantiallycentered within target 81, indicating that the device 50 isapproximately centered over the valve magnet 120. Magnetic capsule 80may also rotate (i.e., spin) with respect to a magnetic capsule axis A′within cavity 70, when the tool magnet 84 aligns with the valve magnet120. In this manner, magnetic capsule 80 may indicate a device 20setting as further described below.

Target 81 may have a shape which is substantially the same as the shapeof magnet 84 or magnetic capsule 80. The target 81 may include a line ora solid (i.e., “filled-in”) shape and may have an outer periphery,perimeter or edge which is the same as or slightly larger than that ofthe tool magnet 84 or magnetic capsule 80. Where the target 81 comprisesan outer periphery that is approximately the same size as the outerperimeter of the magnetic capsule 80, the target 81 will essentially becovered or obscured. Where the target 81 includes an outer peripherythat is larger than the outer perimeter of the magnetic capsule, as canbe seen in FIG. 3B, when the magnetic capsule 80 is centered over thevalve magnet 120, magnetic capsule 80 will move to the center of thetarget 81. For example, magnetic capsule 80 of FIG. 3A moves in thedirection of arrow (AR) to the position shown in FIG. 3B. In FIG. 3B,the outer edge of target 81 can be seen surrounding the centeredmagnetic capsule 80, thereby indicating to a user that the tool 50 iscentered over a valve magnet 120. Similarly, where the perimeter oftarget 81 is the same size as or smaller than the perimeter of the toolmagnet 84 or magnetic capsule 80, covering of the target 81 wouldindicate to a user that the tool magnet and/or magnetic capsule 80 andtherefore the tool 50 is centered or approximately centered over thevalve magnet 120.

FIGS. 4 and 4A depict another embodiment of a magnetic capsule. Magneticcapsule 80′ comprises an arrow-shape and magnets M1, M2 provided in thecapsule 80′. FIG. 4A is a cross sectional view of magnetic capsule 80′,taken along line B-B of FIG. 4. As described above, target 81 maycomprise an arrow shape (not shown) such that magnetic capsule 80′ mayposition itself within the target 81 arrow (not shown) when magnets M1,M2 are positioned over the center of a valve magnet) e.g., 120. Thearrow-shape may advantageously indicate a setting of device 20 such thatrotation of magnetic capsule 80 aligns the tool magnet or magnets 84with the valve magnet 120 causing the arrow to point to a setting on thecentering tool (e.g., 150, 250) or locator tool 26 (FIGS. 9A-9C).

FIGS. 6 and 6A show an embodiment of a combined centering-indicatortool. Centering-indicator tool 150 is similar to centering tool 50 withlike numerals representing like features. As with tool 50, magneticcapsule 80″ is provided within cavity 170 and is configured to centerwithin a target 181 when the magnetic capsule 80″ is centered over avalve magnet (e.g., 120). However, as depicted in FIGS. 6 and 6A,magnetic capsule 80″ further includes a pointer 104. Pointer 104 104 isconfigured to point to a valve setting on an index provided on a locatortool (not shown). Thus, when the centering-indicator tool 150 is used inconjunction with a locator tool (not shown), magnetic capsule 80″ willinteract and align itself with a magnet (e.g., 120) of a valve (e.g.,20). This will cause the pointer 104 to point to a spot on an index of alocator tool (not shown) indicating the position of the magnet of thevalve and thereby will indicate the valve setting. Described anotherway, magnetic capsule 80 moves axially to target 181 while also rotatingor spinning to align with magnet 120 causing pointer 104 to point to thecurrent setting of the adjustable valve 20.

FIGS. 7 and 7A show another embodiment of a combined centering-indicatortool. Combined centering-indicator tool 250 is similar to tool 150(FIGS. 6, 6A) however, tool 250 includes an index 259. Thus, in use,when magnetic capsule 80″ interacts and align itself with a magnet(e.g., 120) of a valve (e.g., 20) and moves to or centers within thecenter of target 281, the interaction will also cause magnetic capsule80″ to rotate or spin causing pointer 204 to point to a spot on index259 indicating the position of the valve magnet 120 and therebyindicating the valve setting.

FIG. 8 shows an example of the interaction between a valve magnet 120and a magnet 84 of a magnetic capsule (e.g., 80, 80′, 80″). In FIG. 8,tool magnet 84 is shown as comprising a horizontal polarity P_(H). Asdescribed above however, vertical polarity of tool magnet 84 is likewisecontemplated. Regardless, as shown in FIG. 8, placement of tool (e.g.,50, 150, 250) above valve 20, causes magnet 84 to magnetically alignwith valve magnet 120 thereby locating magnetic capsule 80, 80′, 80″(and thus tool 50, 150, 250) in alignment with the valve magnet 120. Forease of illustration, additional features of tools 50, 150, 250 such asa target (e.g., 81) and cavity (e.g., 70) are not shown. In addition, asdescribed above, magnet 84 may be comprised of one or more magnets andthe overall effect of the magnetic field of the one or more magnets maybe as depicted in FIG. 8.

An exemplary use of tools 50, 150, 250 is illustrated in FIGS. 9A-9C.FIG. 9A depicts a first step wherein a tool 50, 150 or 250 may be placedwithin a tube 34 of a locator tool 26 which has been previously orientedand aligned with an implanted valve 20 in a similar manner to thelocator tool of the '793 publication, described above. Locator tool 26may include a locator central opening (not shown) through which at leasta portion of the valve 20 is palpated. As a second step, after magneticcapsule 80, 80′, 80″ centers over valve magnet 120, as illustrated inFIG. 9A, tool 50, 150, 250 may be removed from locator tool 26 such asdepicted in such as depicted in FIG. 9B. As described above withreference to locator, indicator and adjustment tools of the '793application, locator tool 26 and tools 50, 150, 250 may includeinteracting alignment features such as grooves, tabs, ridges or slots(not shown) on the outer surface of the tool 50, 150, 250 and innersurface of the locator tool 26 such that a tool 50, 150, 250 may bemechanically engaged with the locator tool 26. In any event, after thecentering tool 50 or combined centering-indicator tool 150, 250 hasidentified the center of the valve magnet 120 (i.e., via tool magnet 84or magnetic capsule 80, 80′, 80″ moving to a target (not shown) asdescribed above), the tool 50, 150, 250 is removed from the locator tool26 while the locator tool is held in the position identified by stepone. As a third step, an adjustment tool 30 may then be placed withinthe tube 34 of the locator tool 26, such as shown in FIG. 9C.Alternatively, if a centering tool 50 was used to indicate the center ofthe valve magnet 120 (i.e., no combined centering-indicator tool wasused in step one), step three may include placement of an indicator tool28 for indicating the setting of a valve and a further step four (notshown) may include removal of the indicator tool and placement of anadjustment tool 30 in a similar manner as placement of a tool such asdepicted in FIG. 9C. In other words, if a centering tool 50 is used tofind the magnetic center of a valve magnet 120, subsequent use of asetting indicator and/or adjustment tool may be carried out in a mannersimilar to that described in the '793 application. Alternatively, if acombined centering-indicator tool (e.g., 150, 250) is utilized to findthe magnetic center of an implanted valve 20 (i.e., find the center ofmagnet 120), and in conjunction with finding the center of the valvemagnet 120, also indicates the current valve setting via pointing to anindex (e.g., 259, FIG. 7) on the tool 250 or an index (not shown) on alocator tool 26 only an adjustment tool, or third step (FIG. 9) would berequired.

Although the present disclosure has been described with reference toparticular embodiments, workers skilled in the art will recognize thatchanges can be made in form and detail without departing from the spiritand scope of the present disclosure.

What is claimed is:
 1. A centering tool for finding the center of anadjustable valve, the tool comprising: a housing including a cavity; amagnetic capsule comprising a tool magnet, the magnetic capsule disposedwithin the cavity; a target; wherein the magnetic capsule is configuredto slide within the cavity and center within the target when the toolmagnet is magnetically aligned with magnet of an adjustable valve. 2.The centering tool of claim 1, wherein the housing includes an upperwall and wherein the magnetic capsule is visible through the upper wall.3. The centering tool of claim 2, wherein the housing comprises acircular-disk shape.
 4. The centering tool of claim 3, wherein the toolmagnet comprises two magnets.
 5. The centering tool of claim 4, whereineach of the two tool magnets comprise vertical polarity with respect toan axis of the magnetic capsule.
 6. The centering tool of claim 5,wherein the magnetic capsule comprises a disk-shape magnetic capsulehousing.
 7. The centering tool of claim 6, wherein the target comprisesa circle having a perimeter larger than a perimeter of the magneticcapsule housing.
 8. The centering tool of claim 7, further comprising afluid contained within the cavity.
 9. The centering tool of claim 8,wherein the magnetic capsule comprises a magnetic capsule housing. 10.The centering tool of claim 9, wherein the magnetic capsule housingcomprises an arrow shape.
 11. The centering tool of claim 1, wherein themagnet comprises a Halbach array.
 12. The centering tool of claim 1,further comprising a metal strip disposed on the top of the tool magnet,wherein the metal strip comprises a thickness less than a thickness ofthe tool magnet.
 13. The centering tool of claim 1, wherein the magneticcapsule is configured to slide along the floor of the cavity.
 14. Thecentering tool of claim 1, wherein the centering tool is configured tofit within a tube of a locator tool.
 15. The centering tool of claim 13,wherein the centering tool comprises a tab along an outer edge, whereinthe tab is configured to interact with a groove on an inner diameter ofthe recess of the locator tool.
 16. A combined centering-indicator toolfor finding the magnetic center and indicating the setting of anadjustable valve, the tool comprising: a housing including a cavity andan index comprising valve setting values; a magnetic capsule comprisinga tool magnet and a pointer, the magnetic capsule disposed within thecavity; a target; wherein the magnetic capsule is configured to movewithin the cavity to center itself within the target when the toolmagnet is magnetically aligned with the magnetic center of theadjustable valve magnet; and wherein the magnetic capsule is configuredto rotate with respect to a magnetic capsule axis such that the pointerrotates to point to a valve setting value on the index.
 17. The combinedcentering-indicator tool of claim 16, wherein the housing includes anupper wall and wherein the magnetic capsule is visible through the upperwall.
 18. The combined centering-indicator tool of claim 17, wherein thetarget comprises a shape substantially similar to a shape of themagnetic capsule and wherein the outer perimeter of the target is largerthan the outer perimeter of the magnetic capsule.
 19. The centering toolof claim 7, further comprising a fluid contained within the cavity. 20.A system for finding the magnetic center and indicating the setting ofan implanted adjustable valve, the system comprising: a locator toolcomprising a tube; a combined centering-indicator tool comprising ahousing including a cavity and an index comprising valve setting values;a magnetic capsule comprising a tool magnet and a pointer, the magneticcapsule disposed within the cavity; a target disposed in the cavity;wherein the magnetic capsule is configured to move within the cavity tocenter itself within the target when the tool magnet is magneticallyaligned with the magnetic center of the adjustable valve magnet; andwherein the magnetic capsule is configured to rotate with respect to amagnetic capsule axis such that the pointer rotates to point to a valvesetting value on the index; wherein the combined centering-indicatortool is configured to be positioned within the tube of the locator toolwhen the locator tool is in proximity to the implanted adjustable valve.